The present invention relates to a heat exchanger.
As is known a heat exchanger is used for transmitting heat from one body to another via one or more metallic or non-metallic surfaces separating the two bodies simultaneously present in the exchanger. These heat exchange surfaces can in particular form one or more enclosures containing the body to be heated.
It is also known that the two thermally contacting bodies may or may not be fluids which may or may not undergo a change of state. In particular the hot body can be a pure body or a eutectic mixture in liquid form solidifying in contact with the hot body, giving off the stored heat in the form of latent heat. As a result of this heat exchange the cold body or heat transfer fluid may vaporize.
The present invention is applicable to the exchanger type, whose hot body is an autonomous heat source. These heat exchangers can be used for air conditioning, underwater air conditioning, solar storage, the recovery of heat, etc.
The known heat exchanger has a number of disadvantages in the case where the hot body is a material which is solidified during heat exchange and the cold body a fluid which vaporizes.
Thus, when the molten heat-storage material and the fluid come into contact via the heat exchange surfaces the material solidifies and suddenly gives off a large quantity of heat, which results in a rapid vaporization of the fluid and therefore causes a considerable increase in the gas pressure. In an irregular manner large vapour or steam bubbles then appear which momentarily obstruct the discharge pipe or pipes. As a result the evaporation operation conditions are unstable (sawtooth phenomenon).
In the special case of air conditioners for skin divers the enclosure or enclosures immersed in the heat-storage material are supplied by a fraction of the sea water flow, i.e. the heat transfer fluid used for heating a diving suit. The vapour emanating from it condenses in a mixer in an irregular manner. This leads to considerable variations in the flow rate of the heat transfer fluid and the temperature. This particular application does not make it possible to consider conventional methods for regulating the temperature and the heat transfer fluid flow, because the weight and overall dimensions of the heat exchanger are limited.